Articles for body fluid absorption such as paper diapers absorb discharges such as urine. Measures against an unpleasant odor during use of or at the time of disposing said body fluid absorption articles have been sought.
Many studies have conventionally been tried on the subject of reducing urine odor. Methods of using an absorbent such as a porous material, methods of using a bactericide, methods of neutralizing odor components with an acid or alkali, and the like have been proposed.
As the technology of utilizing physical adsorption, a number of methods such as a method of using zeolite (Japanese Patent Application Laid-open No. 49-23493/1974, Japanese Utility Model Application Laid-open 75318/1983, etc.), a method of using silica (Published Japanese Translation of PCT Application No. 512944/1999, etc.), a method of using both silica and zeolite (Published Japanese Translation of PCT Application No. 512946/1999, etc.), a method of using activated carbon (Japanese Utility Model Application Laid-open 165126/1982, etc.), and the like have been proposed.
However, methods of using physical adsorption by porous materials and the like have a certain limitation to the adsorption capacity. Occasionally, some adsorbents may reversibly release odor components and other adsorbents exhibit a slow deodorizing rate. In addition, the absorption capacity by pores cannot be effectively utilized in wet conditions immediately after the absorption materials have absorbed urine and the like. It is almost impossible to confirm the deodorizing effect in actual practice.
As attempts for adding a deodorizing function to articles for body fluid absorption such as sanitary napkin and paper diapers, Japanese Patent Application Laid-open No. 272050/1986 discloses an invention of incorporating ethyl alcohol into absorptive layers and Japanese Patent Application Laid-open No. 2345/1992 discloses an invention of incorporating a quaternary ammonium salt such as benzalkonium chloride.
In these inventions, based on the presumption that ammonia produced by decomposition of urea and amino acids in urine by microorganisms or enzymes possessed by the microorganisms is cause of urine odors, an antibacterial agent or a urea decomposition enzyme (urease) inhibitor is incorporated into an absorbing element to suppress ammonia production.
However, the inventors of the present invention have found that no ammonia odor is sensed when replacing a diaper and urine odor does not disappear even if an antibacterial agent is added to urine collected immediately after urination and that the methods of suppressing ammonia production and neutralizing ammonia cannot reduce the unpleasant sensation due to urine odor during wearing or replacing articles for body fluid absorption.
Other technologies that have been heretofore proposed with an objective of deodorizing articles for body fluid absorption such as diapers include a method of using a cation exchange fiber having a deodorizing effect (Japanese Patent Application Laid-open No. 212094/1993), a method of using a deodorizing component obtained from wood vinegar (Japanese Patent Application Laid-open No. 276330/1997), and the like. However, there are no practically effective countermeasures that can reduce unpleasant odors.